from Common import * class SessionStore(Object): """ SessionStores are dictionary-like objects used by Application to store session state. This class is abstract and it's up to the concrete subclass to implement several key methods that determine how sessions are stored (such as in memory, on disk or in a database). Subclasses often encode sessions for storage somewhere. In light of that, this class also defines methods encoder(), decoder() and setEncoderDecoder(). The encoder and decoder default to the load() and dump() functions of the cPickle or pickle module. However, using the setEncoderDecoder() method, you can use the functions from marshal (if appropriate) or your own encoding scheme. Subclasses should use encoder() and decoder() (and not pickle.load() and pickle.dump()). Subclasses may rely on the attribute self._app to point to the application. Subclasses should be named SessionFooStore since Application expects "Foo" to appear for the "SessionStore" setting and automatically prepends Session and appends Store. Currently, you will also need to add another import statement in Application.py. Search for SessionStore and you'll find the place. TO DO * Should there be a check-in/check-out strategy for sessions to prevent concurrent requests on the same session? If so, that can probably be done at this level (as opposed to pushing the burden on various subclasses). """ ## Init ## def __init__(self, app): """ Subclasses must invoke super. """ Object.__init__(self) self._app = app try: from cPickle import load, dump except ImportError: from pickle import load, dump self._encoder = dump self._decoder = load ## Access ## def application(self): return self._app ## Dictionary-style access ## def __len__(self): raise AbstractError, self.__class__ def __getitem__(self, key): raise AbstractError, self.__class__ def __setitem__(self, key, item): raise AbstractError, self.__class__ def __delitem__(self, key): """ Subclasses are responsible for expiring the session as well. Something along the lines of: sess = self[key] if not sess.isExpired(): sess.expiring() """ raise AbstractError, self.__class__ def has_key(self, key): raise AbstractError, self.__class__ def keys(self): raise AbstractError, self.__class__ def clear(self): raise AbstractError, self.__class__ ## Application support ## def storeSession(self, session): raise AbstractError, self.__class__ def storeAllSessions(self): raise AbstractError, self.__class__ def cleanStaleSessions(self, task=None): """ Called by the Application to tell this store to clean out all sessions that have exceeded their lifetime. """ curTime = time.time() for key, sess in self.items(): if (curTime - sess.lastAccessTime()) >= sess.timeout() or sess.timeout()==0: del self[key] ## Convenience methods ## def items(self): return map(lambda key, self=self: (key, self[key]), self.keys()) def values(self): return map(lambda key, self=self: self[key], self.keys()) def get(self, key, default=None): if self.has_key(key): return self[key] else: return default ## Encoder/decoder ## def encoder(self): return self._encoder def decoder(self): return self._decoder def setEncoderDecoder(self, encoder, decoder): self._encoder = encoder self._decoder = decoder ## As a string ## def __repr__(self): d = {} for key, value in self.items(): d[key] = value return repr(d)